the physics of leaning a bike
- Thread starter bhawksworth
- Start date
Too interesting to pass up, I like thinking about this stuff.
To make the problem a little easier to understand and visualize.
replace the ball in the straw with a cup of water sitting on your tank.
And think about what happens when you are holding a cup of coffee going around a turn in your cage You lean it into a turn balance the forces, and it doesn't spill.
Also the variables that make things difficult in the real world, jerky motion, uneven road surfaces, etc need to be removed, so for accurate repeatable results you need smooth motion, in all planes.
When a bike is in a turn, there are 2 forces we are dealing with, gravity always perpendicular through the earth’s center of mass, and the lateral cornering force, perpendicular to the gravitational force.
These forces are balanced by leaning.
If gravitational force exceeds your lateral force, then you fall. If you are going too slow, and lean too far over, Boom, Gravitational forces exceed lateral forces.
If Lateral forces exceed gravitational forces, You wipe out, slide, Highside, lowside. Boom Your lateral force, pushes you to the outside of the turn, more than can be balanced by gravity.
So based on this I would think, the predictable ball movement should be remains somewhat neutral, however because we do not live in a perfect world, the results would be sporadic at best.
If the requirement is to cancel a turn signal, I would use a pendulum type device, that canceled any signal, in any direction, and in the normally low speed environment where turnsignals are used it would probably be pretty accurate.
To make the problem a little easier to understand and visualize.
replace the ball in the straw with a cup of water sitting on your tank.
And think about what happens when you are holding a cup of coffee going around a turn in your cage You lean it into a turn balance the forces, and it doesn't spill.
Also the variables that make things difficult in the real world, jerky motion, uneven road surfaces, etc need to be removed, so for accurate repeatable results you need smooth motion, in all planes.
When a bike is in a turn, there are 2 forces we are dealing with, gravity always perpendicular through the earth’s center of mass, and the lateral cornering force, perpendicular to the gravitational force.
These forces are balanced by leaning.
If gravitational force exceeds your lateral force, then you fall. If you are going too slow, and lean too far over, Boom, Gravitational forces exceed lateral forces.
If Lateral forces exceed gravitational forces, You wipe out, slide, Highside, lowside. Boom Your lateral force, pushes you to the outside of the turn, more than can be balanced by gravity.
So based on this I would think, the predictable ball movement should be remains somewhat neutral, however because we do not live in a perfect world, the results would be sporadic at best.
If the requirement is to cancel a turn signal, I would use a pendulum type device, that canceled any signal, in any direction, and in the normally low speed environment where turnsignals are used it would probably be pretty accurate.
i feel that the straw experiment actually doesnt have a lot to do with the leaning part of the physics of the bike.
more a separate set of forces and again too many factors involved
1 does the tube stay horizontal to the horizon or is affixed to the bike where it cannot move
2 is there a vacuum in the tube
3 are the ball bearing and the straw of a size where the ball bearing can overcome friction easily
4 etc,etc.
more a separate set of forces and again too many factors involved
1 does the tube stay horizontal to the horizon or is affixed to the bike where it cannot move
2 is there a vacuum in the tube
3 are the ball bearing and the straw of a size where the ball bearing can overcome friction easily
4 etc,etc.
I think that the most valid points to this thread were made my Busabullet, Postal, and Busahigg. We are speaking more of the force created by inertia rather than centrifugal force. Realize that we are focusing on the ballbearing in the straw at a particular point in time. That being leaning into a curve. It would take quite a bit of speed going into a curve; and the curve would have to be constant (a circle) in order to achieve enough force to move the ball bearing up the straw. Just simply riding a curve at any speed that any of us can muster would not move the ballbearing upward. The ballbearing, for all practical purposes, would stay at the lower end of the straw. Remember that the straw is at the same angle as the motorcycle. Even with the right speed, at most, the ballbearing should raise up to the center of the straw. To reach a speed that would send the ballbearing to the top of the straw, NO motorcycle rider could attain. Don't laugh at my comments please. I may clown around alot, but the brotha does have some skills.
Brian
Brian
If the straw is not spinning or not attached to a spinning object that causes it to move in a circular motion, the the centrifugal or centripital forces won't matter. The ball bearing will fall to the low side if the straw was mounted laterally (port to starboard) with a center point at the center of the bike. Item in the tank bag shift port or starboard when cornering, so will the ball bearing. I use nautical terms as left and right seem to be confused by many on motorvehicles depending on perspective (in/on or looking from front/rear). Port is left as you sit on the bike facing foreward. Starboard is right.
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